Custom built for Baron Conrad Hilton (yes, that Hilton of the famed Hilton Hotels and Resorts), the houseboat features a gorgeous galley kitchen, a four-bunk stateroom and a private upper deck with unbelievable ocean views that speak for themselves.

If that isn't enough to convince you of how rare and wonderful this place is, it should be noted that President Truman wrote most of the iconic Truman Letters while aboard the estate. Casual.